MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (MALAKAS) WARNING NR 11// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 18W (MALAKAS), LOCATED APPROXIMATELY 647 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM CONTINUES TO CONSOLIDATE AS A COLD DENSE OVERCAST FEATURE BUILDS OVER THE SYSTEM. THE INITIAL POSITION IS BASED ON A LOW REFLECTIVITY CIRCULATION FEATURE IN THE 140528Z AMSU- B MICROWAVE SATELLITE PASS WITH FAIR CONFIDENCE. THE INITIAL INTENSITY OF 60 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK ESTIMATES. UPPER LEVEL ANALYSIS ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH MODERATE (15-20 KNOT) VERTICAL WIND SHEAR (VWS). HOWEVER, WATER VAPOR IMAGERY SHOWS A TUTT CELL TO THE NORTHEAST THAT IS ENHANCING EASTWARD OUTFLOW WHICH IS PROVIDING VENTILATION TO THE CENTRAL CONVECTION. SEA SURFACE TEMPERATURES (SSTS) REMAIN FAVORABLE NEAR 29 CELSIUS. TS 18W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 18W WILL TRACK WEST-NORTHWESTWARD THEN NORTHWESTWARD THROUGH TAU 72. TS MALAKAS WILL BEGIN TO RAPIDLY INTENSIFY AS VWS DECREASES AND OUTFLOW IMPROVES. THE SYSTEM WILL REACH A PEAK OF 120 KNOTS BY TAU 48. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH THIS PORTION OF THE FORECAST; HOWEVER, THE CONSENSUS TREND CONTINUES TO SHIFT THE TRACK TO THE WEST, CLOSER TO TAIWAN. C. IN THE EXTENDED FORECAST, TS 18W WILL REACH THE WESTERN EXTENT OF THE STEERING STR AND TURN NORTHEASTWARD INTO THE STRONG MID- LATITUDE WESTERLIES, MAKING LANDFALL IN KYUSHU JUST AFTER TAU 96. STRONG VWS WILL GRADUALLY WEAKEN THE CYCLONE AS IT ACCELERATES NORTHEASTWARD. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT DURING THIS PORTION OF THE FORECAST; HOWEVER, DUE TO THE INSTABILITY OF THE MULTI-MODEL CONSENSUS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN